1. Field of the Invention
The present invention relates to a manufacturing method of a honeycomb structure. More particularly, it relates to a manufacturing method of a honeycomb structure that can improve a manufacturing efficiency and can also improve a raw material yield.
2. Description of the Related Art
In various fields of, e.g., chemistry, electric power, steel, and others, a honeycomb structure formed of ceramics superior in heat resistance and corrosion resistance is adopted as a carrier or a filter for a catalytic device that is used for, e.g., environmental measures or recovery of specific materials. In particular, the honeycomb structure is recently vigorously utilized as a diesel particulate filter (DPF) which has a plugged honeycomb structure obtained by alternately plugging cell opening portions on both end surfaces and traps a particulate matter (PM) discharged from, e.g., a diesel engine. Further, a silicon carbide (SiC), cordierite, or an aluminum titanate (AT) which is superior in heat resistance and chemical stability is preferably used as a material for the honeycomb structure utilized in a corrosive gas environment at a high temperature.
Since the silicon carbide has a relatively high thermal expansion coefficient, a defect may occur in a large honeycomb structure formed by using the silicon carbide as an aggregate due to, e.g., a thermal shock at the time of use. Further, a defect may also occur due to a thermal shock at the time of burning a trapped particulate material to be removed. Therefore, when manufacturing a honeycomb structure of a predetermined size or a larger size that is formed by using the silicon carbide as an aggregate, a plurality of small plugged honeycomb structure segments are usually manufactured, these segments are bonded to each other to form one large bonded body, and an outer periphery of this bonded body is subjected to rough processing and grinding, thereby obtaining a plugged honeycomb structure having a desired shape, e.g., a cylindrical shape (see, e.g., JP-A-2003-291054). It is to be noted that the segments are bonded to each other using a binder, and the binder is applied to predetermined side surfaces of the segments so that the plurality of segments are bonded to each other on the side surfaces thereof.
When manufacturing a honeycomb structure having a desired shape by using such a method, usually, a plurality of rectangular solid segments must be bonded to form one large rectangular solid bonded body, then an outer periphery of this body must be subjected to rough processing to obtain a substantially desired shape, and grinding must be performed to accurately provide a desired shape, thereby obtaining the honeycomb structure having a desired shape. Therefore, there is a problem that extra manufacturing steps, e.g., rough processing step or a grinding step of the outer periphery are required and a raw material yield is reduced because the outer periphery is subjected to rough processing and grinding.